Dryer felt arrangement



Feb. 18, 1958 E. D. BEACHLER DRYER FELT ARRANGEMENT Filed March 16, 1956 [r7 Var? [Ur firm/Pp D. 5540/ El? United States Patent DRYER FELT ARRANGEMENT Edward D. Beachler, Beloit, Wis., assignor to Beloit Iron Works, Beloit, Wis., a corporation of Wisconsin Application March 16,1956, Serial No. 572,132

2 Claims. -(Cl. 34-117 This invention relates to a dryer section arrangement for paper machines, and more particularly, to an improved felt arrangement for paper machine dryer sections.

In the usual paper machine dryer section, there are provided a plurality of tiers of paper dryer rolls. Ordinarily only an upper tier and lower tier are provided with a plurality of parallelly aligned rolls in each tier. The rolls .or drums provide a shell which is heated internally with steam and which is freely rotatable. The paper weaves a serpentine path through the dryer passing beneath a first 'roll in the lower tier then over a first roll in the upper tier, .and then back down beneath the second roll -in ,the lower tier, etc. Upper traveling looped felts pass :over the tops of each of the rolls in the upper tier so as ;to engage the paper web during most of its travel on such rolls and thus control and assist in removal of moisture from the web. There are also provided traveling looped lower felts trained over the bottoms of the rolls in the :lower tier :so as'to cover the paper web during most of its travel @on the rolls of the lower tier. In the present high speed paper machines, the dryer section is so long that more than one upper felt and more than one lowerfelt are required :in each case. In such instance, a first'upper felt will .cover the tops of a first plurality of rolls in the upper tier and then be directed away from the upper ,tier

of rolls; and a second upper felt will cover a second plurality of dryer rolls :in this :tier immediately adjacent to the first plurality. The second feltis direced by guide means from a felt dryer to the first of the plurality of rolls which this felt covers in.the tier. This occurs atthe so-called break? in .the .upper felts (where one felt "is directed away from the last roll of one plurality or group of rolls and the second felt is directed toward the first roll in the next group of rolls).

At higher paper machine speeds, however, it has been noticed that a disproportionately great number of breaks occur in the web in the region of the so-called felt break. The instant invention is based upon not only the discovery of the causes for such breaks in the web but also the discovery of means for overcoming this difficulty.

Heretofore, the felt at the felt break which was moving in toward the tier of rolls turned to produce a pumping effect, in that it carried along a substantial amount of air therewith. This air was apparently forced into a chamber defined in part by unsupported stretches of paper web extending between the dryer drums. The force of the air against the unsupported stretches of paper web is now believed to be the cause for the excessive number of breaks in the web in this region.

In the practice of the instant invention, this pumping effect by the oncoming or second felt is overcome by directing the second felt initially against a paper web covered portion of a dryer roll. In other words, the first felt is urged against a portion of the web covered region of a dryer drum and then directed away from the tier; and the second felt is urged against another portion of "ice the same web covered region of the dryer drum. :In this way, it is possible to effectively seal off the interior portion of the dryer between the tiers of drums and to prevent the pumping of air into such interior portion.

It is, therefore, an important object of the instant 1nvention to provide an improved felt arrangement for paper machine dryer sections.

It is a further object of the instant invention to provide a paper machine dryer section comprising a dryer roll having a surface region thereof lapped by a paper web, a first felt urged against a first portion of the web covered surface region and a second felt separate and apart from the first felt urged against a second portion of the web covered surface region spaced from said first portion.

Other and further objects, features and advantages of the present invention will become apparent to those skilled in the art from the following detail disclosure thereof and the drawings attached hereto and made a part hereof.

On the drawings:

Figure 1 is essentially a diagrammatic view of a paper machine dryer section showing the prior art arrangement; and

Figure 2 is essentially a diagrammatic arrangement of a paper machine dryer section embodying the instant invention.

As shown on the drawings:

In Fig. 1, a paper machine dryer section of the prior art, indicated generally by the reference numeral 10, comprises an upper tier of dryer rolls 21, 22, 23 and 24, and a lower tier of dryer rolls 31, 32, 33, 34 and 35 (some shown only partially). The direction of travel of the rolls in each case is indicated by an arrow; and it will be appreciated that a paper web W lapped about each of the rolls 21, 22, etc. and 31, 32, etc. travels in the direction indicated by the rotation of the rolls. A first upper felt 40 passes "under a guide roll 41 over a web covered top surface region of the roll 21, under another guide roll 42, over the top web covered surface of dryer roll 22, aroundanother guide roll 43 and then away from the upper tier, as indicated :by the arrow. A second :felt 44 passes along a downwardly directed felt run 44a and around a guide roll 45 and then onto .the top of the dryer roll .23. As will be noted the second felt 44 continues beneath the guide roll 46 over the top 'of the dryer'rolli i and beneath the guide roll 47.

i The downwardly directed felt run 44a of the second felt 44, however, carries with it a substantial amount of air at the rapid speed at which the felt 44 is traveling and this air is forced into a chamber C defined by adjacent top rolls 22 and 23, a bottom roll 33 and unsupported reaches of the web x and y. This results in the application of additional stretching forces, for example, against the unsupported web reach x.

In like manner, a first bottom felt 50 guided by guide rolls 51, 52 and 53 is urged against the bottom on web covered surface regions of the first group of bottom rolls 31, 32 and 33 and the felt 50 is then directed away from the bottom tier. A second felt 54 guided by guide rolls 56 and 57 is urged against the bottom web covered portions of the next group of bottom rolls 34 and 35. The upwardly directed run 54a of the second bottom felt 54 serves also to pump air upwardly between the tiers of rolls and to accomplish additional stretching of an unsupported web reach 2. In addition there is a so-called chimney effect in the dryer section 10 because of the tendency for warm air in the basement to rise upwardly into the dryer section 10. Such warm air rises along with the air that is pumped by the upwardly directed felt run 54a and further adds to the problems here involved. The pumping effect is believed to be the most harmful, however.

. 3 Since the individual felt dryers (not shown) for, for example, the lower felts 50 and 54 are ordinarily spaced apart a substantial distance, the usual practice heretofore has beento direct the off running first felt run 50a and the oncoming second felt run 54:! in opposite'directions, as here shown. This has been the usual paper machine arrangement for years.

a Referring now to Fig. 2, which shows a dryer section 100 embodying the instant invention, it will be seen that this dryer section 100 has an upper tier comprising a first plurality of rolls 121, 122 and a second plurality of rolls 124, 125 (shown partially). A single roll 123 is also mounted in the tier intermediate the first and second pluralities of rolls 121, 122 and 124, 125. It will be seen from the travel of the web W (indicated by arrows showing direction of rotation of the rolls) that each of the rolls 121, 122, 123, etc. has a traveling paper web covered surface region, whose angular size on the periphery of the roll 23 is indicated by A. A first felt 140 is urged against the (top) web covered region of each of the first plurality of rolls 121, 122 by guide rolls 141, 142 and 143. An additional guide roll 143a cooperates with the guide roll 143 to urge the first felt 140 against a first portion 123a of the web covered region (A) of the single roll 123; and the guide rolls 143, 143a are so positioned as to effect the removal of the felt 140 from the surface of the roll 123 after the felt has traveled thereon over the relatively limited portion 123a.

A second felt 144 directed by guide rolls 145, 146 and 147 is urged against the web covered region of each of the second plurality of rolls 124, 125; and, in addition, the guide rolls 145 and 146 urge the second felt 144 against a second portion 12311 of the web covered region (A) of single roll 123. The guide rolls 145, 146 urge the felt 144 against only the limited surface portion 123b and then remove the felt 144 from the surface of the roll 123. It will be noted that the surface portions 123a and 1231; are peripherally spaced from each other and both are within the web covered region (A).

Referring to the lower tier in the dryer section 100, it will be seen that a similar felt arrangement is provided. In the lower tier there are dryer rolls 131, 132, 133, 134 and 135. Also, there are guide rolls 151, 152, 153, 155, 156, 157 and 158.

Referringspecifically to the three rolls 132, 133 and 134 which are mounted in succession, it will be noted that each of such rolls has a traveling paper web covered surface region, whose peripheral angular connection is indicated at B on the roll 133. The first felt 150 is urged against the web covered region of the roll 132 and against a first portion 133a of the web covered region B of the second roll 133. A second felt 154 separate and apart from the felt 150 is urged against a second portion 133b, peripherally spaced from the first portion 133a, of the web covered region B of the roll 133 and the felt 154 is also urged against the web covered region of the next roll 134.

It will be seen that the instant felt arrangement, which involves changing felts in a dryer at a given roll (123 or 133) rather than between rolls completely eliminates the pumping effect which has been found to cause web damage. Also, any tendency for hot air to rise through a chimney effect from the basement up into the dryer section is also prevented.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. In a tier of paper dryer rolls in a paper machine dryer section, first, second and third dryer rolls mounted in succession, each roll having a traveling paper web covered surface region, a first felt urged against the web covered region of the first roll and against a first portion of the web covered region of the second roll, and a second felt separate and apart from the first felt urged against a second portion, spaced from the first portion of the web covered region of the second roll and also urged against the web covered region of the third roll.

2. In a paper machine dryer section, a first plurality of rolls mounted in one tier, a second plurality of rolls mounted in the same tier, a single roll mounted on said tier intermediate the first and second pluralities of rolls, each roll having a traveling paper web covered surface region, a first felt urged against the web covered region of each of said first plurality of rolls, first guide means urging said first felt against a first portion of the web covered region of said single roll and then removing the felt therefrom, a second felt urged against the web covered region of each of said second plurality of rolls, and second guide means urging said second felt against a second portion of the web covered region of said single roll and then removing the felt therefrom.

Mellentine Nov. 17, 1936 Hornbostel Dec. 23, 1947 

